Both great and small is an inclusive way of speaking of all levels of Israelite society (compare “from the least to the greatest” in 6.13). Good News Translation and Die Bibel im heutigen Deutsch have “The rich and the poor.” A number of translations have “high and low” (New International Version, Revised English Bible, Moffatt), while New Jerusalem Bible has “high or low.”
They shall not be buried is similar to verse 4.
Cut himself or make himself bald for them: These were actions to show grief, and consequently the two clauses appear in Good News Translation as “gash himself or shave his head to show his grief.” These practices were forbidden in Deut 14.1, but were evidently practiced by the people of Jeremiah’s day (see 41.5). From the manner in which the law of Deut 14.1 is worded, it would seem that these actions originally held a religious significance for the Canaanite peoples.
Quoted with permission from Newman, Barclay M. and Stine, Philip C. A Handbook on Jeremiah. (UBS Helps for Translators). New York: UBS, 2003. For this and other handbooks for translators see here .